Method and apparatus for selectively isolating a zone of subterranean formation adjacent a well

ABSTRACT

A selective completion, or isolation, tool for isolating a selected zone of subterranean formation adjacent a well, characterized by modular construction for isolating the zone regardless of its thickness; a pair of top and bottom inflatable packer modules and a plurality of modules connected therebetween, each of the modules having an annular space for circulating cement and having structural integrity and a plurality of mating half joints for making up to any predetermined length. Also disclosed are specific structural embodiments and the methods made practical by the improved isolation tool.

United States Patent 1 Doggett et al.

METHOD AND APPARATUS FOR SELECTIVELY lSOLATING A ZONE 0F SUBTERRANEAN FORMATION ADJACENT A WELL Inventors: Glenn 0. Doggett; Bobby Joe Hallmark, both of Fort Worth, Tex.

Gearhart-Owen Industries lnc., Fort Worth, Tex.

Filed: Feb. 27, 1974 Appl. No.: 446,422

Assignee:

US. Cl 166/285, 166/186, 166/187, 166/191, 166/147, 166/276 Int. Cl E21b 33/14, E2lb 43/04, E2lb 33/124 Field of Search 166/187, 276, 285, 278, 166/305, 295, 307, 311, 308, 312, 142, 147, 148, 126, 127, 185, 186, 224

References Cited UNITED STATES PATENTS 4/1958 Conover 166/187 X [451 Feb. 11,1975

3,059,699 10/1962 Brown 166/191 X 3,194,312 7/1965 Thomas 166/147 X 3,430,701 3/1969 Canada 166/186 X 3,456,725 7/1969 Hatch 166/187 X Primary Examiner-Stephen J. Novosad Attorney, Agent, or Firm-Wofford, Felsman, Fails &

Zobal [57] ABSTRACT A selective completion, or isolation, tool for isolating a selected zone of subterranean formation adjacent a well, characterized by modular construction for isolating the zone regardless of its thickness; a pair of top and bottom inflatable packer modules and a plurality of modules connected therebetween, each of the modules having an annular space for circulating cement and having structural integrity and a plurality of mating half joints for making up to any predetermined length. Also disclosed are specific structural embodiments and the methods made practical by the improved isolation tool.

14 Claims, 10 Drawing Figures FRJENTEU F591 1 I95 SHEET 10F 3 ITEM FEB] 1 IS? SHEET 2 OF 3 o 4, lull Wk A PATENTED 1 SHEET 3 OF 3 METHOD AND APPARATUS FOR SELECTIVELY ISOLATING A ZONE OF SUBTERRANEAN FORMATION ADJACENT A WELL BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a type of well packer apparatus referred to as selective completion, or isolation, tools for shielding or protecting a zone within a well penetrating subterranean formation and to a method of using the isolation tool for optimizing fluid flow into or from such zone; for example. for producing oil or gas from such a zone.

2. Description of the Prior Art Isolation tools are a type of completion tools that have packer elements at their top and bottom ends. Such isolation tools employing the inflatable packer elements are known. They are useful in completing an oil well to produce fluid from a given zone after drilling is complete and are beneficial in preventing contact of the producing zone with the cement that is employed to cement the casing in place. In addition, such isolation tools having respective valve means have eliminated costly perforations of the casing and consequent damage to the casing and cement by explosive charges. Other advantages of the inflatable packer type isolation tools have been realized through reduction of completion time and expense, use of the tools in series to reduce chances of communication between close producing zones and selected stimulation and testing of a well during the completion operation.

The closest prior art of which we are aware are US. Pat. Nos. 3,l94,3l2 and 3,456,725. The equipment of the former patent employs many matching portholes and a long production control valve inside the tool for aligning portholes. A possible disadvantage of this tool is that the portholes allow sand to accumulate and block movement of the long production valve. Moreover, the valve moves in a unitary way and does not provide selectively openable and closable sets of ports or portholes. Equipment described in the latter patent uses short inflatable packers that are located on the ends of concentrically spaced sleeves to effectively seal off the formation. It, too, has valves that are opened at a predetermined pressure and not thereafter closable. Moreover, the valves open simultaneously such that the ports are not selectively and individually controllable to allow the flexibility that is desirable. With the equipment of both of the prior art patents, the total length of the tool is limited by the height of the derrick that is used to install it since the tools are unitary tools and must be pre-prepared to a predetermined length. For example, it thus has been impossible heretofore to provide such a tool for isolating a zone that was thicker than the drilling rig was tall. This in effect limited such tools to isolating zones of less than about 90 feet, since most drilling rigs cannot handle longer sections of conduit.

We have found it advantageous that an isolation tool have the following features not heretofore provided by the prior art.

I. The tool should be modular in concept such that any length tool can be assembled at the well site, yet have an annular passageway between inner and outer pipe and through the tool for circulation of cement.

2. Each of the modules should have structural integrity to suspend the weight of the conduit therebelow by either the inner pipe or the outer pipe.

3. The modules should have at their respective ends, joint halves that can be joined to form an interconnection means in which only one set of threads need to be made up and still effect a sealing connection of respective sections of both the inner and outer pipes.

4. The isolation too] should have a plurality of valve modules that have individually and selectively openable and closable valves for controlling the flow through ports therethrough and allow the flexibility of washing the formation, emplacing sand control material, or producing from or injecting into the formation.

Accordingly, it is an object of this invention to provide an isolation tool having one or more of the forgoing features not heretofore provided by the prior art, thereby alleviating the difficulties of the prior art.

It is another object of this invention to provide an isolation tool having all of the delineated features not heretofore provided by the prior art; and to provide methods of employing the isolation tool for optimizing flow of fluids through the well.

It is a speciflc object of this invention to provide an isolation tool that is economical and easy to transport and install; that can be assembled at the well site in as long an isolation tool as desired, even sufficient to cover zones thousands of feet in thickness, without being limited to the height of the rig with which they are being installed; and that has a plurality of production control valves that are respectively, individually and selectively openable and closable and to provide a high degree of flexibility, including at least two different methods of operation employing the added flexibility not heretofore possible.

These and other objects will become apparent from the following descriptive matter, particularly when taken in conjunction with the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A, 1B and IC are respective cross sectional elevational views of the top and bottom sections of the isolation tool and the lower end of a string of conduit having the isolation tool connected thereinto; all in a pre-emplacement configuration within the well.

FIGS. 2A, 2B and 2C are respective cross sectional elevational views of the embodiment of FIGS. 1A, 1B and 1C and show the emplaced configuration after the packers have been inflated.

FIG. 3 is a cross sectional view taken along the lines III-III of FIG. 18.

FIG. 4 is a longitudinal cross sectional view showing an interconnection means of the embodiment of FIGS. 1A and 1B being made up, or connected.

FIG. 5 is a cross sectional elevational view, partly schematic, of another embodiment of this invention being employed to circulate a fluid across the face of an isolated zone intermediate inflated packers.

FIG. 6 is a cross sectional elevational view, partly schematic, of an embodiment of this invention similar to that of FIG. 5, but configured to produce fluid from the zone through the production ports intermediate the top and bottom ports.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIGS. IA and 1B, the selective completion, or isolation, tool 11 is shown positioned within a wellbore 13 that has been drilled into subterranean formation in a conventional manner. The isolation tool 11 is shown connected into a conventional tubular string of conduit, such as casing 15; the bottom end 17 thereof being illustrated in FIG 1C in a typical embodiment. The isolation tool 1 1 is positioned in the wellbore 13 adjacent a zone 19 that is to be isolated. The zone 19 may be a producing subterranean formation or a zone that is producing an objectionable fluid, such as water, into a wellbore that is being drilled by air or gas drilling or the like; or any other zone that needs to be isolated for whatever reason. The limits of the zone 19, such as the impermeable upper and lower formations 21 and 23 may be delineated by suitable logs, such as produced by a gamma ray logging tool. The zone 19 may be substantially homogeneous, such as a sand stone, or may have discontinuous and inhomogeneous strata or vugs 25 therein. One advantage of this invention is that the zone 19 may have any thickness; for example, many times the height of a conventional drilling rig being used to run the casing 15 into the wellbore 13.

In any event, the isolation tool 11 is so formed that the packer modules will be positioned for effecting, when inflated, isolation of the zone 19 longitudinally from the remainder of the wellbore 13; for example, opposite the impermeable strata 21 and 23. If desired, any zone within a subterranean formation of even encompassing several subterranean formations can be isolated by proper placement of the packer modules.

The isolation tool 11 includes a plurality of serially connected modules, as indicated hereinbefore. At the top and the bottom of the serially connected modules are the top and bottom packer modules 27 and 29. The packer modules 27 and 29 have respective expansible packer elements in the form of inflatable jackets 31. The packer modules also include respective outer tubular sections, or sleeves, 33 that carry the respective inflatable jackets 31. The inflatable jackets 31 may be formed of any suitable material; for example, from Nylon reinforced rubber, such as Neoprene, that is resistant to wellbore fluids. The inflatable jackets 31 with their integral steel clamps, or bands, 35 at their respective ends are premanufactured and slipped into the outer tubular sections 33. Suitable seals, such as o-rings 37, are interposed between the respective steel bands 35 and the outer tubular sections 33 to ensure that no fluid is lost when the jackets 31 are inflated. Retainer rings 38 are thereafter welded in place to hold the in flatable jackets against the shoulders 40 at their other end. The process of inflating the jackets is frequently referred to as inflating the packers" and is also referred to herein as inflating the packer modules as a shorthand description of the complete process.

For inflating the inflatable jackets 31, the respective packer elements include conduit means, such as tube 39. The tubes 39'are connected with respective check and block valves 41; and, thence, with suitable inflation valves 43.

The check and block valves 41 allow fluid to flow through the tube 39 to inflate the inflatable jacket 31 up to a predetermined pressure. After the predetermined pressure is reached, suitable means, such as a shear pin, is sheared, or released, and a valve block moved to close off the ports and prevent flow of fluid into or out of the inflated jacket 31. The check and block valves 41 are conventional and need not be de- 4 scribed in detail herein; being described, for example, in U.S. Pat. N0..3,456,725.

The inflation valve 43 may comprise any of the conventional inflation valves. As illustrated, the inflation valve 43 communicates interiorly of the casing 15 by way of a shear-off cover 45. The cover 45 is sheared off by any suitable means; such as, a wireline tool or a plug pumped down the casing 15 under pressure; to open the tube 39 to the fluid pressure interiorly of the casing 15.

The tubular sections 33 that carry the inflatable jackets 31 are fixedly concentrically disposed about respective sections of inner pipe 47 and 49. Thus, the respective outer tubular sections 33 and the sections of inner pipe 47 and 49 define respective annular passageways through the respective packer modules 27 and 29 for circulation of cement therethrough. As can be seen, the inflation valves 43 at their shear-off covers 45 penetrate laterally through the walls of the respective sections of inner pipe 47 and 49 so the tubular sections 33 and the respective sections of inner pipe 47 and 49 also are fixed longitudinally with respect to each other, as will become apparent from descriptive matter later hereinafter. The respective sections of inner pipe 47 and 49 are adapted for being connected into the conduit string. Specifically, the top of the section of inner pipe 47 and the bottom of the section of inner pipe 49 have conventional threads for being threadedly connected into a coupling, such as coupling 51, FIG. 1A.

To provide the desired length of isolation tool to effect placement of valve modules at the top and bottom ofthe zone 19, a plurality of modules, such as extension modules 53 and valve modules 55, are serially connected together in a set intermediate the top and bottom packer modules 27 and 29. The ends of the set of the plurality of modules are connected, respectively, with the top and bottom packer modules 27 and 29. As many of the respective modules as desired can be made up at a well site as the conduit, such as the casing 15, is lowered into the wellbore 13. Ordinarily, the respective modules have certain features in common that facilitate the preparation of the isolation tool of the desired length and with the desired placement of the valve modules 55. For example, the respective extension and valve modules 53 and 55 include the following common structural features that are illustrated most clearly with respect to the extension module 53 in FIGS. 1A, 1B, 3 and 4. They include a section of inner pipe 57; a section of outer pipe 59; a plurality of force transferspacer means, such as ribs, or lugs, 61; and interconnection means 63 connecting the respective modules to contiguous modules.

The respective sections of inner pipe 57 are connected sealingly and serially into a string of inner pipe and the conduit string, such as casing 15, as by threaded connection. The respective sections of inner pipe 57 have adequate structural strength to sustain the weight of the conduit string therebelow in the well and sustain the torque of making up a connection between the modules on the drilling rig floor. For example, when being suspended from a travelling block on a rig, each section of inner conduit 57 must be able to support the weight of the casing 15 therebelow.

The respective sections of outer pipe 59 are connected sealingly and serially into an outer string of conduit, as by threaded connection. The sections of outer pipe 59, similarly as the sections of inner pipe 57, have adequate structural strength to sustain the weight of conduit string therebelow in the well and sustain thej torque of making a connection between modules. For example, as will be described with respect to FIG. 4 hereinafter, when set with slips 64 on the floor 65 of a rig, the respective sections of outer pipe 59 must be able to withstand the weight of the conduit string therebelow, as well as sustain the torque of making up a connection between the modules.

Ordinarily, the same type of steel pipe that is being employed for the casing is employed for the respective sections of inner and outer pipe 57 and 59; only the diameter is different so as to define an annular passageway 67 therebetween. The annular passageway 67 is provided for circulation of a cement slurry for cementing the isolation tool in place in the wellbore 13, as will become apparent hereinafter.

At least three ribs, or lugs, 61 are fixedly connected, respectively, with the sections of inner and outer pipe 57 and 59 for maintaining them in fixed concentric and longitudinal relationships. Thus, the lugs 61 maintain the annular passageway 67. The lugs 61 are connected, as by welding, so as to have adequate structural strength and sustain the weight of the conduit string therebelow in the well and sustain the torque of making a connection between modules and be able to transfer the stress to either the inner or the outer pipe as appropriate. As illustrated, the lugs 61 are welded onto a coupling 69 and are inserted to a point opposite a weldthrough aperture 71, FIG. 1B. The coupling 69 forms a section of greater strength than the remainder of the section 57 of inner pipe and affords a better base for the connection of the lugs 61. The aperture 71 is employed for convenience in welding the lugs 61 to the section of outer pipe 59. The aperture 71 is then filled with metal, further enhancing the strength of the force transfer-spacer means formed by the lugs 61.

The interconnection means 63 includes first and second mating joint halves 73 and 75. The first mating joint half 73 is inserted into the second mating joint half 75. Specifically as illustrated, the top of the respective sections of inner pipe 57 have a female threaded section, such as defined by coupling 69, for receiving a male threaded connection. As illustrated, the respective sections of inner pipe 57 are threadedly connected with the coupling 69 by way of threaded interconnection 87. In like manner, the bottom end of the respective sections of inner pipe 57 have a male threaded section 77 that conformingly screws into a sealing fit with the coupling 69.

The top of the section of outer pipe 59 has a female cylindrical section 79 that conformingly receives a male cylindrical section 81 that is formed onto the bottom of the contiguous module thereabove. Specifically, the female cylindrical section 79 comprises a precisely formed annular recess having a smooth interior surface for sealing. In like manner, the male cylindrical section 81 is formed by a sub 83 that is connected with the bottom end of the section 59 of outer pipe of the contiguous module thereabove and has a precisely formed, smooth male cylindrical surface for sealing. The sub 83 may be connected onto the bottom end of the section of outer pipe 59 by any suitable means, such as by welding. A resilient seal means, such as o-rings 85, are provided intermediate the laterally juxtaposed female and male sealing cylinders 79 and 81 to ensure a sealing interconnection therebetween.

As illustrated in FIG. 4, in connecting the modules the male threaded section 77 of this embodiment is screwed almost into its sealing position; for example, lacking only about five rounds of thread; before the male cylindrical section 81 begins to be inserted within the female cylindrical section 79. This reduces the wear on the resilient seal means as compared with having to rotatingly engage the interior surface of the female cylindrical section 79 throughout the entire rotation of the respective threaded section 77 in the coupling 69.

An annular passagway 67 is defined circumferentially about the coupling 69 and interiorly of the sub 83 for circulation of cement through the interconnection means. Thus, any one of the modules can be readily connected with any one of the contiguous modules by the simple expedient of making up one threaded connection, simultaneously effecting a sealing interconnection between the respective sections of inner and outer pipe so as to form a continuous string of inner and outer pipe with the annular passageway 67 therebetween for circulation of cement slurry, regardless of the length of isolation tool.

In addition to the structural features that are common to both the valve modules and the extension modules, the valve modules 55 also include a plurality of laterally extending ports 91 and a valve means 93, FIG. 1B. The plurality of laterally extending ports each define a passageway penetrating laterally through the respective sections of inner and outer pipe 57 and 59 and the annular passageway 67 therebetween. The plurality of laterally extending ports 91 are spaced apart circumferentially about the section of inner and outer pipes 57 and 59; and within a distance of less than one foot along the respective sections of inner and outer pipe 57 and 59 in order that the valve means can be operated into the closed or open position. This obviates one disadvantage of the prior art apparatus that required moving a long section of valve means with the attendant danger that it will become sanded up and immovable. As illustrated, a plurality of eight ports 91 are disposed in a single plane such that they occupy only about the diameter of the ports; namely, about 74 to l inch. Any number of ports may be employed as desired. Ordinarily, about the minimum that will be employed will be four diametrically opposed ports 91. We have found that about eight ports affords a nearly ideal number although as many as 16 or more may be employed if they are staggered. The ports may be opened for production of fluids or injection of fluids therethrough. They may have suitable accessories, such as sand screens 95, FIGS. 5 and 6, emplaced thereacross. The sand screens 95 may take any of the conventional forms. For example, they may comprise the conventional cylindrical sand screens that are affixed in place, as by welding, about the circumference of the section of outer pipe 59. On the other hand, they may comprise so-called finger screens. The finger screens are emplaced in the respective ports 91 and have many small apertures penetrating longitudinally of the screens and laterally through the ports 91. These finger screens are ordinarily formed of ceramic or other material that is resistant to both corrosion and erosion. or abrasion; yet are foraminous, or permeable, to the flow of fluids therethrough. They may be emplaced by any suitable means. such as C-clamps or mounting rings screwed into the respective ends of cylindrical ports 91.

The valve means 93 includes a sealing surface 97 and a valve 99 that sealingly engages the sealing surface and is selectively movable into an open position to allow fluid to flow through the ports 91 and the interior of the section of inner pipe and into a closed position to block flow of fluid through the ports. Specifically, the sealing surface 97 is illustrated as being formed on a portion of inner wall of the section of inner pipe 57 and terminates at each end in internal thread 101 into which are screwed the mating ends 103 of the remainder of the section of inner pipe 57. The sealing surface 97 is carefully formed as an elongate cylinder for slidably receiving a sleeve valve; and is polished so as to be smooth for effecting a good seal when engaged by the valve 99. As illustrated, the valve 99 comprises a mating sleeve valve having respective seal means, such as o-rings 105, embedded in annular grooves in its peripherally outermost surface for ensuring a seal with the sealing surface 97. The valve 99 has an internal large annular recess 107 intermediate its ends for receiving dogs 109, FIGS. 6, for being moved into its respective open and closed positions. The dogs 109 are operable between a disengaged, or retracted, position in a valve operating tool 111 for passing through the respective sleeve valves, such as sleeve valve 99A, FIG. 5. The dogs may then be selectively expanded into their engaging, or expanded, position, such as illustrated in FIGS. and 6. The dogs may be operated by any suitable means; such as, by electric motor by relative motion between the external section 108 held by drag springs 110 and an inner section 112 rotated by tubing 113. The valve operating tool is normally run into the well on a suitable string, such as tubing 113.

The respective modules may be slightly modified to form specialty combinations of two or more of the modules that are most frequently employed. For example, it is ordinarily advantageous to have a double module with a valve module 55A, FIG. 1A, at the top of a respective zone 19 adjacent the top packer module for either washing the face of the zone adjacent the wellbore 13, effecting a sand control material, or for producing or injecting fluids through the face of the zone. Such a widely used double module modification is illustrated in FIG. IA in which the top valve module 55A is integrally formed with the top packer module 27. Therein, the section of inner pipe 47 of the packer module 27 is threadedly connected into the internal thread 101 of the section of inner pipe 57 of the valve module 55A adjacent the sealing surface 97. Thereafter, the respective sections of inner pipe that are threadedly connected together are also welded to ensure they do not become separated or leak. In a similar manner, the bottom end 115 of the outer tubular section 33 is sealingly emplaced interiorly of a female top end 117 of the section of outer pipe 59. A joinder ring 119 is employed to reinforce the joint and the top and bottom ends are then welded together similarly as were the interior threaded ends of the inner pipe. A plurality of lugs 61 are fixedly connected, as by welding, to the respective sections of inner and outer pipe so as to maintain their concentric relationship defining the annular passageway 67.

Typically, the bottom end of the casing will terminate in a sub that contains a receptacle 121, FIG. 1C, for receiving a pump-down plug, as well as a check valve 123. After a pump-down plug 125 and ball 131 is received, the ball 131 is sheared out at a predetermined 8 pressure after the packer elements are inflated, FIG. 2C.

In operation, the bottom packer module 29 is connected into the conduit string, such as casing 15. The bottom packer module 29 has at its top end a coupling 69 and female cylindrical section 79 ready to receive the next contiguous section. Thereafter, the next contiguous module, such as valve module 55, is stabbed into the top of the bottom packer module 29 and screwed into place, simultaneously effecting sliding sealing interconnection between the outer tubular section 33 and the section of outer pipe 59. Similarly, the next contiguous module. such as extension module 53, will be stabbed into and sealingly connected with the top of the valve module 55. The remaining plurality of modules will be similarly serially and sealingly connected together to effect the desired length and placement of the respective modules in the isolation tool 11. Finally, the top valve module 55A and the top packer module 27 will be stabbed and sealingly connected with the top of the extension module 53, as illustrated in FIG. 1A. The remainder of the casing is thereafter threadedly connected together and until the desired length is achieved sufficient to emplace the top and bottom packer modules 27 adjacent the impermeable strata 21 and 23 defining the limits of the zone 19 and against which the respective packers can be inflated to seal and isolate the zone 19. In the run-in, or pre' emplacement, configuration the respective valves 99 are in their closed positions for effecting a desired pressure interiorly of the sections of inner pipe and casing 15.

As illustrated in FIGS. 2A, 2B and 2C, a pump-down plug is thereafter pumped down the casing 15, shearing the shear-off covers 45 from the inflation valves 43. The pump-down plug 125 comes to rest in the pump down receptacle 121, FIG. 2C. Thereafter, pressure is effected by pumping the fluid down the interior of the casing 15, inflating the respective inflatable jackets 31 of the packer modules 27 and 29 so they sealingly engage against the respective impermeable strata 21 and 23 at the wall of the wellbore 13. When a predetermined pressure has been reached, the check and block valves 41 close, thereafter preventing fluid flow into or out of the inflated jackets 31. For example, at about 250 pounds per square inch (psi) a shear pin in each check and block valve 41 is sheared, trapping the fluid in each inflated packer.

Thereafter, the casing pressure can be increased up to 1,000 psi or more to shear a pin in the pump-down plug, release a plug ball 131 and allow cement to be circulated. The cement slurry is circulated; for example,

downwardly through the casing and back up through the annular space between the casing and the wall of the wellbore 13, as well as through the annular passage way 67 through the isolation tool. The cement slurry may be circulated completely back to the surface or for only a predetermined distance above and below the isolation tool 11. In this way the face of the formation is isolated from contact with a cement slurry to prevent the resultant damage that frequently occurs from such cementing operations. Thereafter, a valve operating tool 111 is lowered through the casing 15 and the respective valves 99 are moved as desired to configure the well for flow of fluids therethrough. For example, the valves 99 may be moved into their open positions such that the respective ports 99 produce fluids from the zone 19 into the interior of the casing 15. If desired, the fluids may be produced through the casing. It is common practice in producing operations, however, to insert tubing 113 with a production packer 133 to protect the casing and force the fluids to flow upwardly through the tubing 113, as illustrated in FIG. 6. The production packers 133 are well known and need not be described in detail herein. It is sufficient to note that they ordinarly have a resilient seal 135 that can be expanded into sealing contact with the interior of the section of inner pipe 57. If set above open valves 99, the set production packer isolates the annular passageway intermediate the exterior of the tubing 113 and the interior of the casing and constrains fluid to flow through the tubing 113. If set between open valves 99, the production packer converts the annular passageway into a separate and return flow passageway for circulation of fluid flowed downwardly through the interior of the tubing 113.

If desired, the valve operating tool 111 may be suspended by any other suitable means, such as by wireline, for moving the respective valves 99 into their open position by pulling upwardly thereon. Conversely, if the valves are to be moved into their closed position, a wireline with jars suspending the valve operating tool 111 is employed. In the latter case, the dogs 109 are expanded into the recess I07 and the valve closed by jarring downwardly thereon.

One advantage of this invention is that a variety of different embodiments of the isolation tool can be prepared for a great flexibility in operation. For example, the respective top and bottom packer modules may be employed with only extension modules th'erebetween if it is desired to isolate a formation that is producing water into a well being drilled by air or gas drilling. If, on the other hand, subsequent control of flow of fluids into or from the'isolated zone 19 could be necessary, it is advisable to employ one or more valve modules. Ordinarily, the valve modules will be disposed at least near the top and bottom of the formation, particularly where it is desired to wash the face of the formation to rid it of flow restricting material, such as drilling mud filter cake and the like; effect sand control material; or otherwise treat the zone 19. Thus, in an isolation tool similar to that illustrated in FIGS. 2A and 2B, the tubing 113 with the valve operating tool 111 and the production packer 133 may be emplaced interiorly of the casing 15 and the respective top and bottom valves; similar to valves 99A and 99B, FIGS. 5 and 6; will be moved into their open positions.

Thereafter, a wash fluid is flowed serially through one of the open top or bottom valves, longitudinally along and in contact with the face of the zone I9 to wash flow-restricting materials from the face of the zone and through the other of the open ports. For example, as illustrated in FIG. 5, the wash fluid is circulated downwardly through the tubing 113, outwardly through open ports 918, along the face of the formation and back inwardly through the top open ports 91A and, thence, upwardly in the annular passageway between the tubing 113 and the section of inner pipe 57 and the casing 15. After the zone has been suitably washed, the tubing and production packer may be moved upwardly within the casing above the open top valve 99A and fluids produced through the tubing 113. If desired, the intermediate valve 99C may be opened in FIG. 5, although it is not shown in the embodiment of FIGS. 2A and 28. If, on the other hand, the well is to be completed as an injection well, fluids may be injected downwardly through the tubing I13 and into the isolated zone 19. The production packer 133 will be emplaced above the top open valve 99A so as to constrain the flow of fluid interiorly of the tubing 113 when the tubing and production packer are employed.

If desired, of course, the tubing may be employed alone without the production packer 133 and such open annulus completions are sometimes advantageous in helping to unload a well, as by injecting gas into the annulus to blow liquids up the tubing and prevent liquid loading that would stop production.

In any event, the isolation tool of this invention can be employed in any of the usual well configurations, whether injection or production, and still achieve its advantages as delineated in more detail hereinafter.

Another embodiment that is frequently useful in zones 19 that normally produce sand with their production fluids may be understood by referring to FIGS. 5 and 6, specifically. Therein, the top valve 99A and the bottom valve 998 are moved into their open positions as described hereinbefore, leaving the intermediate valve module 55C with its valve 99C in the closed position. As can be seen, the top and bottom sets of ports 91A and 91B do not have any sand screens in place whereas the at least one intermediate set of ports 91C do have the sand screens 95 emplaced therein, or extending across the ports. Moreover, while only one intermediate valve module SSC is illustrated, as many as desired may be employed for effecting the requisite length tool and the requisite production capability for producing fluids from the zone 19. After the isolation tool has been emplaced and cemented into place as described hereinbefore and the respective top and bottom valve modules opened, as illustrated, a fluid effecting a sand control material is circulated past the face of the zone 19; for example, downwardly through the tubing 113, upwardly across the face of the zone 19, back in through the top ports 91A and thence upwardly through the annular space between the tubing and the casing.

The terminology fluid effecting a sand control material is employed herein, even though it is awkward; since there are a wide variety of different types of sand control materials that are effected by different ways. For example, the oldest and simplest is the so-called gravel pack in which gravel or sand within a controlled size range are injected in a carrier fluid and allowed to settle in the annular space between the exterior surface of the sections of outer pipe 59 and the face of the zone 19 and intermediate the top and bottom packer mod ules 27 and 29. This is the embodiment that is illustrated in which the gravel 139 is illustrated emplaced in FIG. 6. It should be readily appreciated, however, that any of the fluids effecting sand control material may be employed. For example, a fluid may be flowed along and into the passageways of the face of the formation to set and consolidate the sand grains at their points of contact and prevent movement of the sand toward the wellbore, yet allow fluid to be produced through the open pores and passageways therebetween. This type of sand consolidation material may take a wide variety of forms from those fluids that are set by heat, such as furfural alcohol and the like, to those catalytically set agents, such as the epoxy resins, regardless of whether the latter employ a time-setting single fluid or another and catalystcontaining fluid to effect the desired setting. Typical of the wide variety of sand control agents that are conventional and well known are the following: Sand Bond l-lV: Sandpoxy l-Vl; Eposand 9 S, Eposand 112 S; Comp-slurry; Slurry-pack C; Comp-perm C; Exxon E; Continental C; Shell S; Chevron CH and the like. In fact, any fluid that will not pass through the and 1 inch ports 91A and 918 would probably not be satisfactory in effecting a satisfactory sand control material.

In any event, after the sand control material has been effected, by whatever means that is appropriate, the top and bottom valves 99A and 99B are moved into their closed positions, as illustrated in FIG. 6. The one or more intermediate valves 99C are moved into their respective one or more open positions, opening the production ports 91C for flow of fliuds through the sand screens 95. Similarly as described hereinbefore, the production packer 133 is emplaced above the uppermost open set of ports 91C so as to constrain the production fluids to flow through the tubing 113 rather than the annular space between the tubing 113 and the casing 15. This method of production is advantageous in that the fluids from the zone 19 are constrained to flow through the sand control material, illustrated as gravel pack 139, and through the sand screens 95 such that problem with production of sand is alleviated.

If desired, a plurality of respective sets of ports in one or more valve modules may have different sand screens with different size openings or materials or forms of construction emplaced across their respective ports 91 such that empirical data will indicate the best type of sand screen, or size openings, that need to be employed for optimizing production. No other tool has this flexibility.

The respective modules may be prepared in any predetermined lengths that are easily assembled. For example, the extension modules having various lengths of 2, 4, 6, 8. up to 24 feet in length are employed in facilitating making up an isolation tool having the desired length and placement of the valve and packer modules. The valve modules may have any length; for example, in the range of 2-6 feet. A variety of lengths are not particularly helpful, since the valve module has one primary function. We have found that a length of about 3 feet is satisfactory. The packer modules, similarly as the valve modules, may have any length, but ordinarily do not need to vary as much as the extension modules. Packer modules 2-6 feet in length have been found adequate to sealingly engage respective subterranean formations. Ordinarily, a packer module having a packer element about two feed in length is satisfactory.

The respective elements of the isolation tool 11 may be made of any material that will satisfy the requirements delineated hereinbefore for the respective elements.

While an inflatable jacket has been disclosed as the packer element for the packers, the packers may take any other suitable form; for example, a concentric bag that sealingly seats at its radial interior against the outer tubular section 33 and expands outwardly into contact with the wall of the wellbore 13.

Any of the conventional inflation valves may be employed, not only the use of inflation valves having shear-off covers. For example, pressure responsive inflation valves may be employed to inflate the packers only after a predetermined pressure has been reached.

While the respective packer modules 27 and 29 have been illustrated as having their own individual inflation valves 43 and check and block valves 41, a single inflation valve 43 and check and blocck valve 41 may be employed in tubing 39 that extends to both the top and bottom packers 27 and 29 if desired. This structure may be advantageous when shorter tools are made up. lt is ordinarily preferable, however, to have the illustrated structure wherein respective packer sections have their own respective inflation valve and conduit means and the modules may be freely made up without having to bother about the tube running longitudinally of the annular passageway 67.

The three lugs 61 spaced 120 apart circumferentially with respect to the inner and outer pipes have been described. Any number of lugs may be employed as long as they effect the concentric relationship between the inner and outer pipes. For example, four lugs, spaced apart, may be employed if desired.

While the threaded sections of the interconnection means have been described hereinbefore as being on the sections of inner pipe, they could be emplaced on the outer pipe if desired and the respective longitudinally slidable and sealing sections be formed on the sections of inner pipe. The same desirable results are achieved in which a sealing interconnection is made be tween both the sections of inner and outer pipe with making up only one threaded connection.

While a coupling 69 has been illustrated hereinbefore as the female threaded section that is connected to the respective sections of inner conduit by way of threaded connection 87, it is apparent that the female threaded section may be formed integrally with the remainder of the section of inner pipe 57, if desired.

While a sleeve valve and a cylindrical sealing surface have been described hereinbefore for the respective valve means for controlling flow of fluid through the ports 91, any other valve means may be employed as desired. For example, it has been found to be advantageous in certain high pressure installations to employ planar ports and ball plugs that engage respective spherical sealing surfaces for controlling the flow of fluid through the ports. Such ball valves are conventional and need not be described in detail herein.

From the foregoing, it can be seen that this isolation tool is advantageous in that is has the features delineated hereinbefore and not heretofore provided by the prior art. This isolation tool has wide applicability since it is extremely flexible and may be employed in a wide variety of applications.

Specifically, this isolation tool or selective completion tool, permits completion of a well without cement contaminating any of the producing interval; without perforating, since the large ports allow adequate flow without any perforating and since there is no cement sheath around the casing; and without plugging and squeeze cementing each zone that is tested. This isolation tool allows the capability of quickly shutting in any zone without requiring killing of the well, provides the ability to clean the entire face of the production interval and provides a better chance of producing what the drill stem tests indicate the zone is capable of producing. Moreover, the entire formation face is available to accommodate any particular type of treatment that is desired, whether it be merely washing the formation or effecting deposition of a sand control material, such as a sand consolidation material, or any other remedial work. The isolation tool allows fluid to be produced from the entire formation face instead of only the area about a few perforations and effects much better drainage of the zone with lower pressure drop in the immediate vicinity of the wellbore. From a safety point of view, the valves are able to be closed in the casing to shut in a well, in addition to being individually and selectively openable and closable for optimizing production these features not being available in any other tool. Since the ports are large diameter ports; for example, to /8 inch or more, it is possible to achieve high injectivity, whether for acid treatment, water-flood or fracturing with low hydraulic horsepower requirements.

The isolation tool allows a wide variety of special applications in addition to those delineated hereinbefore: For example, lost circulation zones may be isolated to allow continued drilling; zones producing corrosive fluids, such as hydrogen sulfide, may be isolated to protect the remainder of the casing from damage, with or without an openable valve therein for later setting a pancake or other type of protection out in the formation if desired; and multiple tubingless completions may be effected, if desired. As indicated hereinbefore, however, a primary benefit of this isolation tool is that long thicknesses of zones, or producing or injection intervals, can be isolated and configured for flow of fluid easily at the well site because of the modular construction and the other structural features delineated hereinbefore.

From the foregoing, it can be seen that this invention achieves the objects delineated hereinbefore.

Although this invention has been described with a certain degree of particularity, it is understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to without departing from the spirit and the scope of this invention.

What is claimed is:

1. ln apparatus for driling and completing a well penetrating subterranean formations and having a conduit string therein, a selective isolation tool for isolating a zone, comprising a plurality of serially connected modules that include:

a. a plurality of packer modules including at least top and bottom modules; each of said packer modules including an inflatable packer element that is expansible when subjected to fluid pressure therewithin outwardly into sealing contact with the wall of said well; said packer modules including respective outer tubular sections carrying said packer elements and concentrically disposed about respective sections of inner pipe so as to define an annular passageway therebetween; the respective sections of inner pipe being adapted to be connected into said conduit string;

b. inflation valve and conduit means connected with said packer elements and in fluid communication with the interior of said inner pipe;

c. at least one extension module disposed intermediate and connected with said packer modules; said at least one extension module including:

i. a section of inner pipe adapted to be connected sealingly and serially into said conduit string and having adequate structural strength to sustain the weight of conduit string therebelow in said well and sustain the torque of making a connection between modules;

ii. a section of outer pipe adapted to be connected sealingly and serially into an outer string of conduit and having adequate structural strength to sustain the weight of conduit string therebelow in said well and sustain the torque of making a connection between modules;

iii. a plurality of force transfer-spacer means connected respectively with said inner and outer pipes and maintaining them in fixed concentric and longitudinal relationship with adequate structural strength to sustain the weight of conduit string therebelow in said well and sustain the torque ofmaking a connection between modules; said concentric relationship defining an annular passageway between said inner and outer pipes; and

iv. interconnection means for connecting respective modules to contiguous modules; said interconnection means including first and second mating joint halves, said first joint half being disposed at one end and adapted for inserting into a second joint half; said second joint half being disposed at the other end of said extension module and adapted for receiving said first joint half; said interconnection means including mating and sealing threaded sections on one of said sections of pipe and mating longitudinally slidable and sealing sections on the other of said sections of pipe such that said extension module can be connected to contiguous modules by stabbing and screwing only one set of said threaded sections together and effecting longitudinal sealing interconnection of both said inner and outer pipes;

whereby any predetermined length isolation tool can be made up and either said inner pipe can suspend from a travelling block of a rig and sustain the weight of said conduit string or said outer pipe can be set with slips on said rig and sustain the weight of said conduit string and torque necessary to make up said modules of said isolation tool at said well.

2. The isolation tool of claim 1 wherein said plurality of modules includes at least one valve module intermediate said packer modules, said valve module including:

a. a section of inner pipe adapted to be connected sealingly and serially into said conduit string and having adequate structural strength to sustain the weight of conduit string therebelow in said well and sustain the torque of making a connection between modules;

b. a section of outer pipe adapted to be connected sealingly and serially into an outer string of conduit and having adequate structural strength to sustain the weight of conduit string therebelow in said well and sustain the torque of making a connection between modules;

c. a plurality of force transfer-spacer means connected respectively with said inner and outer pipes and maintaining them in fixed concentric and longitudinally spaced relationship with adequate structural strength to sustain the weight of conduit string therebelow in said well and sustain the torque of making a connection between modules; said concentric relationship defining an annular passageway between said inner and outer pipes;

d. interconnection means for connecting respective modules to contiguous modules; said interconnection means including first and second mating joint halves, said first joint half being disposed at one end and adapted for inserting into a second joint half; said second joint half being disposed at the other end of said extension module and adapted for receiving said first joint half; said interconnection means including mating and sealing threaded sections on one of said sections of pipe and mating longitudinally slidable and sealing sections on the other of said sections of pipe such that said extension module can be connected to contiguous modules by stabbing and screwing only one set of said threaded sections together and effecting longitudinal sealing interconnection of both said inner and outer pipes;

e. a plurality of laterally extending ports, each defining a passageway penetrating laterally through said inner and outer pipes and the annular passageway therebetween; and

f. a valve means having a sealing surface and a valve that sealingly engages said sealing surface and is selectively movable into an open position to allow fluid to flow through said ports and said interior of said inner pipe and into a closed position to block flow of fluid through said ports; said ports being spaced apart circumferentially of said pipes and disposed within a longitudinal distance therealong of less than one foot.

3. The isolation tool of claim 2 wherein said plurality of modules includes a plurality of said valve modules intermediate said packer modules; and said valves are individually and selectively movable, respectively, into said open and closed positions.

4. The isolation tool of claim 3 wherein said valve means is a sleeve valve means; said sealing surface is defined by a section of an internal wall of said inner pipe such that said ports penetrate laterally through said sealing surface; and said valve is a sleeve valve that is movable to cover and uncover said ports in the respective closed and open positions; said sleeve valve sealingly engaging said sealing surface about said ports when covering said ports and having a length of less than two feet such that said sleeve valve can be readily moved into its open and closed positions.

5. The isolation tool of claim 3 wherein said top packer module and said top valve module are contiguous and are integrally connected together with the outer tubular section of said packer module being sealingly and fixedly connected at its bottom end to the top end of said section of outer pipe of said valve module and with the bottom end of the section of inner pipe concentrically interiorly of said outer tubular section of said packer module being integrally sealingly and fixedly connected to the top end of said section of inner pipe of said valve module; and a plurality of at least three spacer means are fixedly disposed intermediate the respective sections of inner and outer pipe near the bottom of said outer tubular section so as to maintain an annular passageway through both said top packer and top valve modules.

6. The isolation tool of claim 2 wherein said first mating joint half includes a male threaded end on said inner pipe and a male cylindrical section on said outer pipe; said second mating joint half includes a female threaded end on said inner pipe and on said outer pipe a female cylindrical section that conforminly receives said male cylindrical section; and a seal means is provided intermediate said male cylindrical section and said female cylindrical section for sealing when they are slid together in lateral juxtaposition.

7. The isolation tool of claim 6 wherein said female threaded end comprises a coupling that is connected to said inner pipe; said force transfer-spacer means includes at least three lugs that are welded to said coupling and said outer pipe; said lugs being angularly spaced apart sufficiently to effect said concentrically fixed relationship between said inner and outer pipes.

8. ln apparatus in a well having a conduit string therein and penetrating subterranean formations, a downhole isolation tool isolating a zone of subterranean formation for optimizing production thereform by any one of a plurality of methods, comprising a plurality of serially connected modules that include:

a. a plurality of inflated packer modules including at least top and bottom modules; said packer modules including respective packer elements that are sealingly inflated against the wall of a well near, respectively, the top and bottom of said zone and isolating said zone longitudinally from the remainder of said well; said packer modules including respective outer tubular sections carrying said packer elements and concentrically disposed about respective sections or inner pipe so as to define an annular passageway therebetween; the respective sections of inner pipe being connected into said conduit string adjacent said zone;

b. inflation valve and conduit means holding said packer elements inflated and preventing flow of fluid into or out of said packer elements;

c. a set of a plurality of valve modules and extension modules serially connected together intermediate said packer modules and connected with, respectively, said top and bottom packer modules; respective said valve and extension modules includmg:

i. a section of inner pipe connected sealingly and serially into said conduit string and having adequate structural strength to sustain the weight of said conduit string therebelow and sustain the torque necessary for making and breaking a con nection between one of the casing and the modules;

ii. a section of outer pipe connected sealingly and serially into an outer tubing string conduit and having adequate structural strength to sustain the weight of casing therebelow and sustain the torque of making and breaking said connection;

iii. a plurality of force transfer-spacer means connected respectively with said inner and outer pipes and maintaining them in fixed concentric and longitudinal relationship with adequate structural strength to sustain the weight of said casing therebelow and sustain the torque of making and breaking said connection; said concentric relationship defining an annular passageway between said inner and outer pipes;

iv. interconnection means connecting the respective modules to contiguous modules; said interconnection means including first and second mating joint halves with said first mating joint half being inserted into a second mating joint half; said inter connection means including mating and sealing threaded sections on one of said sections of pipe and mating and longitudinally slidable and sealing sections on the other of said sections of pipe such that said contiguous modules are sealingly connected via one screwed and sealing connection and via one longitudinally slidable and sealing connection;

said valve modules including, in addition:

v. a plurality of laterally extending ports, each defining a passageway penetrating laterally through said inner and outer pipes and the annular passageway therebetween; and

vi. a valve means having a sealing surface and a valve that sealingly engages said sealing surface and is selectively movable into an open position to allow fluid to flow through said ports and said interior of said inner pipe and into a closed position to block flow of fluid through said ports; said ports being spaced circumferentially of said pipes and disposed within a longitudinal distance therealong of less than one foot;

a first valve module of said valve modules being disposed adjacent the top of said zone and a second valve module of said valve modules being disposed adjacent the bottom of said zone.

9. The downhole isolation tool of claim 8 wherein said conduit string is casing; said casing is cemented in place by a sheath of set cement extending for respective distances above and below said top and bottom packer modules in said well and a sheath of set cement fills said annular passageway intermediate the respective sections of inner and outer pipe and said sections of inner pipe and said outer tubular sections of said packer modules; said first and second valve modules have their respective valves moved into respective said open positions; an inner string of tubing extending from the surface is disposed interiorly of said inner pipe; said inner string of tubing has a production packer expanded into sealing contact with the walls of said inner pipe intermediate said first and second valve modules; and a wash fluid is circulated through said first and second valve modules and washes flow restricting material, including drilling mud filter cake, from the face of said zone intermediate said packer modules; said tubing and production packer being movable to configure said well for subsequent fluid flow therethrough.

10. The downhole isolation tool of claim 8 wherein said first and second valve modules are spaced apart by at least one module therebetween and are connected with respective top and bottom packer modules for flowing a fluid effecting a sand control material radially intermediate said zone and the exterior of said outer pipe and longitudinally intermediate said inflated top and bottom packer modules; at least one third valve module having sand screens emplaced across its said ports is disposed intermediate said first and second valve modules and connected into said outer tubular string and said tubular string for producing fluid from said zone and through emplaced sand control material and blocking production of sand and similar particulate material; and said casing is cemented in place by a cement sheath extending for respective distances above and below said top and bottom packer modules in said well and a sheath of set cement fills said annular passageway intermediate the respective sections of inner and outer pipe and said sections of inner pipe and said outer tubular sections of said packer modules.

11. The isolation tool of claim 10 wherein a string of tubing extending from the surface is disposed interiorly of said inner pipe; said inner string of tubing has a production packer expanded into sealing contact with the walls of said inner pipe intermediate said first and second valve modules; said first and second valve modules have their respective valves moved into respective said open positions; said at least one third valve modules has its valve moved into its said closed position; a fluid effecting a sand control material is circulated through said first and second valve modules and longitudinally along the face of said zone therebetween such that said sand control material is effected intermediate said zone and said exterior of said outer pipe for preventing production of sand when fluids are produced from said zone; said tubing and production packer being movable to configure said well for subsequent production.

12. The isolation tool of claim 11 wherein a column of sand control material is effected longitudinally intermediate said packer modules and radially intermediate said zone of formation and said exterior of said outer pipe; said first and second valve modules have their valves moved into the respective closed positions and said at least one third valve module has its valve moved into the open position for producing fluid through said sand control material and said sand screens across said ports.

13. Method of cleaning the face of a zone of a subter ranean formation penetrated by a well from the surface comprising the steps of:

a, running into said well on a conduit string and positioning adjacent said zone a downhole isolated tool having top and bottom inflatable packer elements for isolating said zone and a plurality of selectively and individually openable and closable sets of ports and valve means; said ports communicating interiorly and exteriorly of said conduit string and being opened and closed by said valve means; said inflatable packer elements being concentrically disposed about said conduit string; a first set of said sets of ports and valve means being disposed adjacent the top of said zone and a second set of said sets of ports and valve means being disposed adjacent the bottom of said zone; said isolation tool including a string of outer pipe fixedly and concentrically disposed about a string of inner pipe so as to define an annular passageway therebetween for circulation of cement therebetween and about said ports;

b. inflating said packer elements to isolate said zone and emplace said isolation tool;

c. circulating cement slurry serially through said conduit string, the annular space between said conduit string and said subterranean formations for a distance below said isolation tool, the annular passageway between said inner and outer pipes of said isolation tool, and the annular space between said conduit string and said subterranean formations for a distance above said isolation tool; and allowing said cement to set and cement said conduit string and said isolation tool in place without contact of said zone with said cement slurry;

d. after said cement is set; opening said first and second said sets of ports and valve means;

e. running a string of tubing and a production packer into said isolation tool; expanding said production packer intermediate said first and second sets of ports and valve means; and flowing a wash fluid setion of cement therebetween and about said ports; b. inflating said packer elements to isolate said zone and emplace said isolation tool; circulating cement slurry serially through said casing, the annular space between said casing and said subterranean formation for a distance below said isolation tool, the annular passageway between said inner and outer pipes of said isolation tool, and the annular space between said casing and said subterrially through one of said first and second sets, longitudinally along and in contact with said zone to wash flow restricting materials, including drilling mud filter cake and the like, from the face of said c. zone, and through the other of said first and second sets;

f. stopping the flow of said wash fluid; and

g. configuring said well for flow of fluids through the face of said zone.

14. A method of completing a production well peneranean formations for a distance above said isolatrating subterranean formations in a zone of a formation tool; and allowing said cement to set and cetion that normally produces sand with its production ment said casing and said isolation tool in place fluids, comprising the steps of: without contact of said zone with said cement a. running into said well, casing containing an isolaslurry;

tion tool such that said isolation tool is positioned d. after said cement is set; opening said first and secadjacent said zone; said isolation tool having top end said sets of ports and valve means; and bottom inflatable packer elements for isolating e. running a string of tubing and a production packer said zone and a plurality of selectively and individinto said isolation tool, expanding said production ually openable and closable sets of ports and valve packer intermediate said first and second sets of means; said ports communicating interiorly and exports and valve means; and flowing a fluid effecting teriorly of said casing and being opened and closed a sand control material serially through one of said by said valve means; said inflatable packer elefirst and second sets, longitudinally along and in ments being concentrically disposed about said contact with said zone for effecting a sand control casing; a first set of said sets of ports and valve material and through the other of said first and secmeans being disposed adjacent the top of said zone ond sets; and a second set of said sets of ports and valve f. stopping flow of said fluid effecting a sand control means being disposed adjacent the bottom of said material; and allowing said sand control material to zone; at least one third set of said ports and valve be effected; means having sand screens emplaced across its said g. closing said first and second sets of ports and valve ports and being disposed intermediate said first and means and opening said at least one third set of second sets of ports and valve means; said first, secports and valve means; and v ond and third sets being closed to block flow of h. producing fluids from said zone through said sand fluid through said ports; said isolation tool includcontrol material and said sand screens across the ing a string of outer pipe fixedly and concentrically ports of said at least one third set of ports and valve disposed about a string of inner pipe so as to define means. an annular passageway therebetween for circular- 

1. In apparatus for driling and completing a well penetrating subterranean formations and having a conduit string therein, a selective isolation tool for isolating a zone, comprising a plurality of serially connected modules that include: a. a plurality of packer modules including at least top and bottom modules; each of said packer modules including an inflatable packer element that is expansible when subjected to fluid pressure therewithin outwardly into sealing contact with the wall of said well; said packer modules including respective outer tubular sections carrying said packer elements and concentrically disposed about respective sections of inner pipe so as to define an annular passageway therebetween; the respective sections of inner pipe being adapted to be connected into said conduit string; b. inflation valve and conduit means connected with said packer elements and in fluid communication with the interior of said inner pipe; c. at least one extension module disposed intermediate and connected with said packer modules; said at least one extension module including: i. a section of inner pipe adapted to be connected sealingly and serially into said conduit string and having adequate structural strength to sustain the weight of conduit string therebelow in said well and sustain the torque of making a connection between modules; ii. a section of outer pipe adapted to be connected sealingly and serially into an outer string of conduit and having adequate structural strength to sustain the weight of conduit string therebelow in said well and sustain the torque of making a connection between modules; iii. a plurality of force transfer-spacer means connected respectively with said inner and outer pipes and maintaining them in fixed concentric and longitudinal relationship with adequate structural strength to sustain the weight of conduit string therebelow in said well and sustain the torque of making a connection between modules; said concentric relationship defining an annular passageway between said inner and outer pipes; and iv. interconnection means for connecting respective modules to contiguous modules; said interconnection means including first and second mating joint halves, said first joint half being disposed at one end and adapted for inserting into a second joint half; said second joint half being disposed at the other end of said extension module and adapted for receiving said first joint half; said interconnection means including mating and sealing threaded sections on one of said sections of pipe and mating longitudinally slidable and sealing sections on the other of said sections of pipe such that said extension module can be connected to contiguous modules by stabbing and screwing only one set of said threaded sections together and effecting longitudinal sealing interconnection of both said inner and outer pipes; whereby any predetermined length isolation tool can be made up and either said inner pipe can suspend from a travelling block of a rig and sustain the weight of said conduit string or said outer pipe can be set with slips on said rig and sustain the weight of said conduit string and torque necessary to make up said modules of said isolation tool at said well.
 2. The isolation tool of claim 1 wherein said plurality of modules includes at least one valve module intermediate said packer modules, said valve module including: a. a section of inner pipe adapted to be connected sealingly and serially into said conduit string and having adequate structural strength to sustain the weight of conduit string therebelow in said well and sustain the torque of making a connection between modules; b. a section of outer pipe adapted to be connected sealingly and serially into an outer string of conduit and having adequate structural strength to sustain the weight of conduit string therebelow in said well and sustain the torque of making a connection between modules; c. a plurality of force transfer-spacer means connected respectively with said inner and outer pipes and maintaining them in fixed concentric and longitudinally spaced relationship with adequate structural strength to sustain the weight of conduit string therebelow in said well and sustain the torque of making a connection between modules; said concentric relationship defining an annular passageway between said inner and outer pipes; d. interconnection means for connecting respective modules to contiguous modules; said interconnection means including first and second mating joint halves, said first joint half being disposed at one end and adapted for inserting into a second joint half; said second joint half being disposed at the other end of said extension module and adapted for receiving said first joint half; said interconnection means including mating and sealing threaded sections on one of said sections of pipe and mating longitudinally slidable and sealing sections on the other of said sections of pipe such that said extension module can be connected to contiguous modules by stabbing and screwing only one set of said threaded sections together and effecting longitudinal sealing interconnection of both said inner and outer pipes; e. a plurality of laterally extending ports, each defining a passageway penetrating laterally through said inner and outer pipes and the annular passageway therebetween; and f. a valve means having a sealing surface and a valve that sealingly engages said sealing surface and is selectively movable into an open position to allow fluid to flow through said ports and said interior of said inner pipe and into a closed position to block flow of fluid through said ports; said ports being spaced apart circumferentially of said pipes and disposed within a longitudinal distance therealong of less than one foot.
 3. The isolation tool of claim 2 wherein said plurality of modules includes a plurality of said valve modules intermediate said packer modules; and said valves are individually and selectively movable, respectively, into said open and closed positions.
 4. The isolation tool of claim 3 wherein said valve means is a sleeve valve means; said sealing surface is defined by a section of an internal wall of said inner pipe such that said ports penetrate laterally through said sealing surface; and said valve is a sleeve valve that is movable to cover and uncover said ports in the respective closed and open positions; said sleeve valve sealingly engaging said sealing surface about said ports when covering said ports and having a length of less than two feet such that said sleeve valve can be readily moved into its open and closed positions.
 5. The isolation tool of claim 3 wherein said top packer module and said top valve module are contiguous and are integrally connected together with the outer tubular section of said packer module being sealingly and fixedly connected at its bottom end to the top end of said section of outer pipe of said valve module and with the bottom end of the section of inner pipe concentrically interiorly of said outer tubular section of said packer module being integrally sealingly and fixedly connected to the top end of said section of inner pipe of said valve module; and a plurality of at least three spacer means are fixedly disposed intermediate the respective sections of inner and outer pipe near the bottom of said outer tubular section so as to maintain an annular passageway through both said top packer and top valve modules.
 6. The isolation tool of claim 2 wherein said first mating joint half includes a male threaded end on said inner pipe and a male cylindrical section on said outer pipe; said second mating joint half includes a female threaded end on said inner pipe and on said outer pipe a female cylindrical section that conforminly receives said male cylindrical section; and a seal means is provided intermediate said male cylindrical section and said female cylindrical section for sealing when they are slid together in lateral juxtaposition.
 7. The isolation tool of claim 6 wherein said female threaded end comprises a coupling that is connected to said inner pipe; said force transfer-spacer means includes at least three lugs that are welded to said coupling and said outer pipe; said lugs being angularly spaced apart sufficiently to effect said concentrically fixed relationship between said inner and outer pipes.
 8. In apparatus in a well having a conduit string therein and penetrating subterranean formations, a downhole isolation tool isolating a zone of subterranean formation for optimizing production thereform by any one of a plurality of methods, comprising a plurality of serially connected modules that include: a. a plurality of inflated packer modules including at least top and bottom modules; said packer modules including respective packer elements that are sealingly inflated against the wall of a well near, respectively, the top and bottom of said zone and isolating said zone longitudinally from the remainder of said well; said packer modules including respective outer tubular sections carrying said packer elements and concentrically disposed about respective sections or inner pipe so as to define an annular passageway therebetween; the respective sections of inner pipe being connected into said conduit string adjacent said zone; b. inflation valve and conduit means holding said packer elements inflated and preventing flow of fluid into or out of said packer elements; c. a set of a plurality of valve modules and extension modules serially connected together intermediate said packer modules and connected with, respectively, said top and bottom packer modules; respective said valve and extension modules including: i. a section of inner pipe connected sealingly and serially into said conduit string and having adequate structural strength to sustain the weight of said conduit string therebelow and sustain the torque necessary for making and breaking a connection between one of the casing and the modules; ii. a section of outer pipe connected sealingly and serially into an outer tubing string conduit and having adequate structural strength to sustain the weight of casing therebelow and sustain the torque of making and breaking said connection; iii. a plurality of force transfer-spacer means connected respectively with said inner and outer pipes and maintaining them in fixed concentric and longitudinal relationshiP with adequate structural strength to sustain the weight of said casing therebelow and sustain the torque of making and breaking said connection; said concentric relationship defining an annular passageway between said inner and outer pipes; iv. interconnection means connecting the respective modules to contiguous modules; said interconnection means including first and second mating joint halves with said first mating joint half being inserted into a second mating joint half; said inter connection means including mating and sealing threaded sections on one of said sections of pipe and mating and longitudinally slidable and sealing sections on the other of said sections of pipe such that said contiguous modules are sealingly connected via one screwed and sealing connection and via one longitudinally slidable and sealing connection; said valve modules including, in addition: v. a plurality of laterally extending ports, each defining a passageway penetrating laterally through said inner and outer pipes and the annular passageway therebetween; and vi. a valve means having a sealing surface and a valve that sealingly engages said sealing surface and is selectively movable into an open position to allow fluid to flow through said ports and said interior of said inner pipe and into a closed position to block flow of fluid through said ports; said ports being spaced circumferentially of said pipes and disposed within a longitudinal distance therealong of less than one foot; a first valve module of said valve modules being disposed adjacent the top of said zone and a second valve module of said valve modules being disposed adjacent the bottom of said zone.
 9. The downhole isolation tool of claim 8 wherein said conduit string is casing; said casing is cemented in place by a sheath of set cement extending for respective distances above and below said top and bottom packer modules in said well and a sheath of set cement fills said annular passageway intermediate the respective sections of inner and outer pipe and said sections of inner pipe and said outer tubular sections of said packer modules; said first and second valve modules have their respective valves moved into respective said open positions; an inner string of tubing extending from the surface is disposed interiorly of said inner pipe; said inner string of tubing has a production packer expanded into sealing contact with the walls of said inner pipe intermediate said first and second valve modules; and a wash fluid is circulated through said first and second valve modules and washes flow restricting material, including drilling mud filter cake, from the face of said zone intermediate said packer modules; said tubing and production packer being movable to configure said well for subsequent fluid flow therethrough.
 10. The downhole isolation tool of claim 8 wherein said first and second valve modules are spaced apart by at least one module therebetween and are connected with respective top and bottom packer modules for flowing a fluid effecting a sand control material radially intermediate said zone and the exterior of said outer pipe and longitudinally intermediate said inflated top and bottom packer modules; at least one third valve module having sand screens emplaced across its said ports is disposed intermediate said first and second valve modules and connected into said outer tubular string and said tubular string for producing fluid from said zone and through emplaced sand control material and blocking production of sand and similar particulate material; and said casing is cemented in place by a cement sheath extending for respective distances above and below said top and bottom packer modules in said well and a sheath of set cement fills said annular passageway intermediate the respective sections of inner and outer pipe and said sections of inner pipe and said outer tubular sections of said packer modules.
 11. The isolation tool of claim 10 wherein a string of tubing extending frOm the surface is disposed interiorly of said inner pipe; said inner string of tubing has a production packer expanded into sealing contact with the walls of said inner pipe intermediate said first and second valve modules; said first and second valve modules have their respective valves moved into respective said open positions; said at least one third valve modules has its valve moved into its said closed position; a fluid effecting a sand control material is circulated through said first and second valve modules and longitudinally along the face of said zone therebetween such that said sand control material is effected intermediate said zone and said exterior of said outer pipe for preventing production of sand when fluids are produced from said zone; said tubing and production packer being movable to configure said well for subsequent production.
 12. The isolation tool of claim 11 wherein a column of sand control material is effected longitudinally intermediate said packer modules and radially intermediate said zone of formation and said exterior of said outer pipe; said first and second valve modules have their valves moved into the respective closed positions and said at least one third valve module has its valve moved into the open position for producing fluid through said sand control material and said sand screens across said ports.
 13. Method of cleaning the face of a zone of a subterranean formation penetrated by a well from the surface comprising the steps of: a. running into said well on a conduit string and positioning adjacent said zone a downhole isolated tool having top and bottom inflatable packer elements for isolating said zone and a plurality of selectively and individually openable and closable sets of ports and valve means; said ports communicating interiorly and exteriorly of said conduit string and being opened and closed by said valve means; said inflatable packer elements being concentrically disposed about said conduit string; a first set of said sets of ports and valve means being disposed adjacent the top of said zone and a second set of said sets of ports and valve means being disposed adjacent the bottom of said zone; said isolation tool including a string of outer pipe fixedly and concentrically disposed about a string of inner pipe so as to define an annular passageway therebetween for circulation of cement therebetween and about said ports; b. inflating said packer elements to isolate said zone and emplace said isolation tool; c. circulating cement slurry serially through said conduit string, the annular space between said conduit string and said subterranean formations for a distance below said isolation tool, the annular passageway between said inner and outer pipes of said isolation tool, and the annular space between said conduit string and said subterranean formations for a distance above said isolation tool; and allowing said cement to set and cement said conduit string and said isolation tool in place without contact of said zone with said cement slurry; d. after said cement is set; opening said first and second said sets of ports and valve means; e. running a string of tubing and a production packer into said isolation tool; expanding said production packer intermediate said first and second sets of ports and valve means; and flowing a wash fluid serially through one of said first and second sets, longitudinally along and in contact with said zone to wash flow restricting materials, including drilling mud filter cake and the like, from the face of said zone, and through the other of said first and second sets; f. stopping the flow of said wash fluid; and g. configuring said well for flow of fluids through the face of said zone.
 14. A method of completing a production well penetrating subterranean formations in a zone of a formation that normally produces sand with its production fluids, comprising the steps of: a. running into said well, casing containing an isolation toOl such that said isolation tool is positioned adjacent said zone; said isolation tool having top and bottom inflatable packer elements for isolating said zone and a plurality of selectively and individually openable and closable sets of ports and valve means; said ports communicating interiorly and exteriorly of said casing and being opened and closed by said valve means; said inflatable packer elements being concentrically disposed about said casing; a first set of said sets of ports and valve means being disposed adjacent the top of said zone and a second set of said sets of ports and valve means being disposed adjacent the bottom of said zone; at least one third set of said ports and valve means having sand screens emplaced across its said ports and being disposed intermediate said first and second sets of ports and valve means; said first, second and third sets being closed to block flow of fluid through said ports; said isolation tool including a string of outer pipe fixedly and concentrically disposed about a string of inner pipe so as to define an annular passageway therebetween for circulation of cement therebetween and about said ports; b. inflating said packer elements to isolate said zone and emplace said isolation tool; c. circulating cement slurry serially through said casing, the annular space between said casing and said subterranean formation for a distance below said isolation tool, the annular passageway between said inner and outer pipes of said isolation tool, and the annular space between said casing and said subterranean formations for a distance above said isolation tool; and allowing said cement to set and cement said casing and said isolation tool in place without contact of said zone with said cement slurry; d. after said cement is set; opening said first and second said sets of ports and valve means; e. running a string of tubing and a production packer into said isolation tool, expanding said production packer intermediate said first and second sets of ports and valve means; and flowing a fluid effecting a sand control material serially through one of said first and second sets, longitudinally along and in contact with said zone for effecting a sand control material and through the other of said first and second sets; f. stopping flow of said fluid effecting a sand control material; and allowing said sand control material to be effected; g. closing said first and second sets of ports and valve means and opening said at least one third set of ports and valve means; and h. producing fluids from said zone through said sand control material and said sand screens across the ports of said at least one third set of ports and valve means. 